Burnham asks Ni'Var, the reunited Vulcan and Romulan world, for data that could explain the Burn and faces a trial guided by her mother.
Burnham needs records from Project SB-19 to trace the cause of the Burn, but they are held by Ni'Var, formerly Vulcan, whose people reunited with the Romulans after Spock's efforts and who left the Federation believing SB-19 caused the Burn.
The Ni'Var leaders allow her a T'Kal-in-ket hearing, and her advocate is a member of the Qowat Milat, a sisterhood sworn to absolute candor, who turns out to be her mother Gabrielle. Pushed to face her own motives, Burnham withdraws her request, which so impresses President T'Rina that the data is shared. Saru names Tilly acting first officer. Kirsten Beyer wrote the episode.